Electronic Structure of F Centers: Saturation of the Electron Spin Resonance

作者：Alan M. Portis · 发表于：Physical Review · 年份：1953 · DOI：10.1103/physrev.91.1071 · 被引用次数：585 · 研究领域：Solid-state spectroscopy and crystallography、Electron Spin Resonance Studies、Advanced NMR Techniques and Applications

It is shown that the unusual observed saturation behavior of the microwave electron spin resonance associated with $F$ centers in KCl, NaCl, and KBr crystals can be accounted for if the overall width is ascribed to interaction between the $F$-center electrons and the nuclear magnetic moments of the ions adjacent to the $F$ centers. The measured saturation factor gives for $F$ centers in KCl a spin-lattice relaxation time of 2.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}5}$ sec at room temperature. The observed saturation behavior in which only the absorption saturates is in marked disagreement with the Kramers-Kronig relations. However it is shown, that the Kramers-Kronig relations are not applicable to saturated systems. Expressions which avoid the use of these relations are presented for saturable systems.